Starting and operating circuits and devices for electric discharge devices



Feb. 19, 1952 P w u 2,586,405

STARTING AND OPERATING CIRCUITS AND DEVICES FOR ELECTRIC DISCHARGE DEVICES Filed June 16, 1948 9.6 56 5b 2b 1b 6b 41: /26b lnvervbor: Philippe Wa cguei'.

His A htorne a.

Patented Feb. 19, 1952 STARTING AND OPERATING CIRCUITS AND DEVICE FOR ELECTRIC DISCHARGE DE- ICE Philippe Waguet, Paris, France, assignor to General Electric Company, a corporation of New York Application June,16, 1948, Serial No. 33,387 InFrance .Fune, 14, 1947 4: Claims. 1

This invention relates to electric discharge devices of the type employing ionizable mediums such as gases or vapors, and more particularly to starting and operating devices and circuits therefor.

An object of my invention is to provide a new and improved starting and operating circuit for electric discharge devices energized from a direct current source.

Another object of my invention is to provide an improved and simplified operating circuit for luminous electric discharge devices or fluorescent lamps energized in series from a direct current source, and utilizing an auxiliary dependent alternating voltage source for heating the electrodes and starting the discharge in the lamps by means of an impulse induced therein.

My invention is of general applicability wherever it is desired to operate fluorescent lamps from a direct current supply. It has been found particularly useful in the illumination of cars on electrical railways and permits the immediate utilization of the direct current supplied to the locomotive, for instance the traction supply at 750 or 1500 volts, on the lighting circuits.

A feature of my invention is the utilization of an auxiliary direct-to alternating current con-' verter for heating the filamentary electrodes in the lamp and also for starting the discharge. This is achieved by means of a time-delay relay which permits the utilization of a voltage induced in the armature of the converter, upon the rupture of its field winding circuit, as a starting impulse for the lamps. This induced voltage is communicated to starting electrodes on the lamps-by means ofthe primary circuit of a transformer to the lamp electrodes.

For a more complete discussion of various circuitswhich may be utilized in operating fluorescent lamps from a direct current supply, referwhose secondary circuit provides heating current.

ence is made to my copending U. S. application No. 28,223, filed May 20, 1948. Other applications and improvements in such circuitsare disclosed. in my copending U. S. applications Nos.

28,224, 28,225, and 28,226, filed May 20, 1948, and

ent invention is actually animprovement in the circuit disclosed in application No. 33386; All of tic, view: of; a. plurality of" electric discharge de- 33,385 and-33,386, filed June 16, I948. Thepres vices connected in series and a starting and operating device and circuit therefor incorporating my invention.

Referrin to the drawing, I have there illustrated one embodiment of my invention as applied to a group of two or more serially connected electric discharge devices wherein the notations for device la and the elements associated with device la are extended by indices to the other serially connected device or devices. The electric discharge device In (and lb), such as a fluorescent lamp, therein illustrated compromises an elongated tubular or cylindrical envelope 2a having sealed into the ends thereof thermionicfilamentary electrodes 3a and; Filamentary electrodes 3a and 411 may comprise a coil, preferably in the form of a coiled coil of tungsten wire activated with oxides of alkaline earth metals such as a mixture of barium and strontium oxides. The envelope. 2a contains a gaseous atmosphere such as a rare gas like neon, argon or mixtures thereof at a pressure of a few millimeters and a small quantity of mercury which, during the operation of the lamp, has a low pressure of the order of 10 microns; The device In. may be alow pressure positive column lamp of a fluorescent type provided with a suitable phosphor or fluorescent coating. This fluorescent coating, upon excitation by the radiation produced by an electric discharge between, the electrodes, transforms a shorter wave radiation due to the discharge into longer wave radiation such as radiation within the visible range. A pair of metal cups 5a and 6a serve to intercept the particlesof emissivematerial sputtered from electrodes 3a and 4a, respectively. These cups are usually tied by means of connections, either outside or inside of the lamp, to the extremities 3a and 4a., A- number of advantages result from the connections between fil'amentary electrodes 3a and 4a and: the corresponding cups, 5a and 6a, namely, utilization of cup 6a as an anode and eliminating the disintegration by ionic bombardment of filamentaryelectrode 4a, utilization of lamps that are usually employed with alternating current, reduction of operating voltage, doubling the life of the lamp by using successively the two filamentary electrodes, i-. e-., by turning the lamps around when one of the filaments becomes inoperative;

Serially connected devices la and lb are connected across a suitable direct currentpower supply I, 1' which, for example, may'bea traction voltage of either 750 or- 1500 volts, and in series with an auxiliary'or second direct currentsource of supply8 which, forexample; may be astorage battery having a potentiaP-or 72 ,dynamoelectric machine 3 volts and connected in series with the devices la and lb in such a manner that it will be charged by the current passing through the devices. The direct current source of supply I, I supplies current to devices la, and lb through stabilizing resistances 9a. and 9b. Resistances 9a and 919, for example, may be iron or tungsten wire enclosed in hydrogen. A starting and operating circuit H3, H3 is connected across the auxiliary direct current supply 8 and comprises in series relationship a field winding section II of a dynamoelectric machine or rotary converter l2, a manual make-and-break switch I3, and a switching means l4 comprising a normally closed contactor i5 and a normally open contactor l6. Auxiliary electrodes Na and Nb, mounted ad- Jacent devices id and lb, are connected to a common point [8 intermediate field winding section II and contactors l5 and I6 through an armature winding section i9 of dynamoelectric ma chine I2. The time-delay relay or switching means I4 comprises a coil 20 connected across the terminals of the direct current source of sup- Switching means id, in addition, comprises a normally closed contactor 2| and a normally open contactor 22 in series with each other and with switch i3, armature winding section IQ of the dynamcelectric machine l2, and contactors l5 and i6 across the auxiliary source of direct current supply 8. A time-delay relay or switching means 23 comprising a contactor 24 in series with the direct current source of supply 7, 1 and a coil 25 connected across the auxiliary source of direct current supply 8 energizes the starting and operating circuits for devices la and lb upon closure of switch I3. Thus, contactors l5 and it are connected in series with the conductor which connects the positive terminal of the battery 8 to the point i8, which both the armature winding section l9 and the field winding section II of the dynamoelectric machine l2 have in common. Moreover, the contactors 2| and 22 are connected in series with the conductor which connects the negative terminal of battery 8 with the other terminal of the armature winding section [3 by means of the switch l3, the other terminal of the field windin section H being connected to a common point between switch l3 and contactor 2|.

Transformers 26a and 2% comprising primary winding sections 2751 and 21b and center-tapped secondary winding section 28a and 28b, respectively, are connected in parallel across an alternating current supply 29, 28' produced by the l2. The secondary winding sections 28a and 28b serve to heat filamentary electrodes 4a and 4b and to continue to heat these electrodes as long as primary winding sections Zl'a, and 2??) are energized. The center-tap of the secondary winding section 2% is connected through the ballasting resistance 9a to the filamentary electrode 3c of device la and the center-tap of thesecondary winding section 28a is connected through the auxiliary source of direct current supply 8 to the negative terminal 1 of the direct current supply.

The operation of the circuit illustrated in the drawing is as follows: In the rest position, as shown in the drawing, contactors l6 and 22 are open and contactors I5 and 2| are closed. Upon the closing of the igniting switch I3, the coil 25 of the supply relay 23 is energized, contactor 24 closes and applies the system voltage to coil 20 of relay or switching means l4 and to the series 1 connected lamps in; the entirety. Contactor I6 closes and energizes field winding section I I, contactor 22 closes a few tenths of a second after the closing of contactor l6, and applies voltage to the armature windin section H! of the inverter which now begins to operate. The cathode filamentary electrodes 4a and 4b are heated. After a few seconds contactor 2| opens, interrupts the circuit of armature winding section l9 and discontinues the heating of the cathode filamentary electrodes; a few tenths of a second after the opening of contactor 2| contactor l5 opens and breaks the field winding section circuit thus causing at point H! a voltage impulse which is imparted, through the armature winding section I9, to the auxiliary electrodes Ila, ||b, etc. by way of the primary heating circuit to which these auxiliary electrodes are connected. This voltage impulse is similar to the voltage produced by induction in electrical motors and generators whenever a field windin circuit carrying a steady current is ruptured, as is well known in the art. Under the efiect of that impulse the discharge lamps la, lb, etc. ignite. If the system voltage should fail, relay or switching means l4 would immediately return to the rest position, contactors |5 and 2| would close, contactors I6 and 22 would open, and the armature and field circults of the inverter would be open. When the normal system voltage is reestablished, switching means M functions as described above and the lamps in their entirety are thus re-ignited. Switching means i4 is so adjusted that it will return to the rest position only when the system voltage is slightly above the voltage at which the series connected lamps no longer will operate. If the system voltage drops below that value, switching means HI will return immediately to the rest position, just as in the case of no voltage.

It is evident that the device which has just been described for a group of series-connected lamps can also be applied to any number of these groups connected in parallel.

The delayed operation of the contactors l5, "5, 2| and 22 of switching means M may be brought about, for example, by means of a mechanism actuated by coil 20 that causes the tilting of two glass bulbs containing mercury, the flow of which, suitably retarded by a capillary tube, serves to make or break the contacts. Other means for carrying out the switching function, such as mechanical timing devices for instance, will occur to those skilled in the art.

While a certain specific embodiment has been shown and described, it will, of course, be understood that various modifications may be made without departing from the invention. Thus,

whereas a pair of lamps connected in series has :and modifications as fall within the true spirit and soopeof the invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. Apparatus for operating a gaseous luminous electric discharge device, of the type including a main thermionic electrode and a cooperating main electrode, comprising: said device, a unidirectional voltage source, and a ballast resistance; arotaryconverter having a direct current field winding, a direct current input circuit, and an alternating current output circuit; a transformer having a primary Winding connected to said output circuit and a secondary winding connected to said thermionic electrode; a-main discharge circuit constituted by connecting said device, in series with said ballast resistance, across said source; a time delay relay having two sets of contacts respectively connecting said field winding and said input circuit across said source, said relay operating to energize in sequence, first said field Winding and then said input circuit, and said relay then operating to de-energize in sequence, after a predetermined time interval, first said input circuit and then said field winding, and an auxiliary starting electrode on said device connected to one side of the primary winding of said transformer for receiving the voltage induced in said output circuit upon the de-energizing of said field winding.

2. Apparatus for operating a gaseous luminous electric discharge device, of the type including a main thermionic electrode and a cooperating main electrode, comprising: said device, a unidirectional voltage source, and a ballast resistance; a dynamoelectric machine for converting direct current to alternating current, said machine comprising a field winding and an armature having direct current input terminals and alternating current output terminals; a transformer having a primary winding connected to said output terminals and a secondary winding connected to said thermionic electrode; a main discharge circuit constituted by connecting said device, in series with said ballast resistance, across said source; a time delay relay having two sets of contacts respectively connecting said field winding and the input terminals of said armature across said source, said relay operatin to energize in sequence, first said field winding and then said armature, and said relay then operating to de-energize in sequence, after a predetermined time interval sufiicient to permit heating of said thermionic electrode, first said armature and then said field winding; and an auxiliary starting electrode, located intermediate the ends of said device, connected to one of said alternating current output terminals, said auxiliary electrode thereby receiving, as a starting impulse, the voltage induced in said armature upon the de-energizing of said field winding.

3. Apparatus for operating a plurality of discharge devices, of the type including a main filamentary thermionic electrode and a cooperating main electrode, comprising: said devices, a unidirectional voltage source, and a ballast resistance; a dynamoelectric machine for converting direct current to alternating current, said machine comprising a field winding and an armature having direct current input terminals and alternating current output terminals; a transformer havin a primary winding connected to said output terminals and a plurality of secondary windings connected to said filamentary electrodes; a main discharge circuit constituted by connecting said devices in series, the secondary winding associated with one device being connected to the cooperating main electrode of another in sequence, and the remaining secondary winding and cooperating electrode being connected, in series with said ballast resistance, across said source; a time-delay relay having two sets of contacts respectively connecting said field winding and the input terminals of the said armature across said source, said relay then operating to ole-energize in sequence, first said field Winding and then said armature and said relay then operating to de-energize in sequence, after a time interval suificient to permit the heating of said filamentary electrodes, first said armature and then said field winding; and auxiliary electrodes, located'intermediate the ends of said devices, connected to one of said alternating current output terminals, said auxiliary electrodes thereby receiving, as a starting impulse, the voltage induced in said armature upon the de-energizing of said field winding.

4. Apparatus for operating a plurality of discharge devices of the type including a main filamentary thermionic electrode and a cooperating main electrode, comprising: said devices, a unidirectional voltage source, and a ballast of resistance; a dynamoelectric machine for converting direct current to alternating current, said machine comprising a field winding and an armature having direct current input terminals and alternating current output terminals; a transformer having a primary winding connected to said output terminals, and a plurality of secondary windings connected to said filamentary electrodes; a main discharge circuit constituted by connectin said devices in series, the secondary winding associated with one device being connected to the cooperating main electrode of another in sequence, and the remaining secondary winding and cooperating electrode being connected, in series with said ballast resistance, across said source; a storage battery connected in series between said main discharge circuit and said source, the polarity connections of said battery being such as to permit charging of same by the discharge current through said devices; a time-delay relay having two sets of contacts respectively connecting said field winding and the input terminals of said armature across said battery, said relay operating to energize, in sequence, first said field winding and then said armature, and said relay then operating to deenergize in sequence, after a time interval sulficient to permit heating of said filamentary electrodes, first said armature and then said field winding; and auxiliary starting electrodes, located intermediate the ends of said devices, connected to one of said alternating current output terminals, said auxiliary electrodes thereby receiving, as a starting impulse, the voltage induced in said armature upon the de-energizing of said field winding.

PHILIPPE WAGUET.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,814,499 Von Wedel July 14, 1931 1,844,375 Wiegand Feb. 9, 1932 1,977,231 Erickson Oct. 16, 1934 2,020,731 Lederer Nov. 12, 1935 2,236,195 McKesson Mar. 25, 1941 2,253,185 Lord Aug. 19, 1941 2,456,859 Campbell Dec. 21, 1948 2,462,328 Mills Feb. 22, 1949 FOREIGN PATENTS Number Country Date 861,198 France Oct. 22, 1940 

